keeping in mind that parallel lines have exactly the same slope, let's check for the slope of the equation above
[tex]3x+2y=8\implies 2y=-3x+8\implies y=\cfrac{-3x+8}{2} \\\\\\ y=\cfrac{-3x}{2}+\cfrac{8}{2}\implies y=\stackrel{\stackrel{m}{\downarrow }}{-\cfrac{3}{2}}x+4\qquad \impliedby \begin{array}{|c|ll} \cline{1-1} slope-intercept~form\\ \cline{1-1} \\ y=\underset{y-intercept}{\stackrel{slope\qquad }{\stackrel{\downarrow }{m}x+\underset{\uparrow }{b}}} \\\\ \cline{1-1} \end{array}[/tex]